1. Field of the Invention
The present invention generally relates to a hemming machine, which hems an edge part of a workpiece, and an inspecting method thereof.
2. Background Information
A hemming machine is often used to bend a peripheral edge of a first panel over a peripheral edge of a second panel. One example of a conventional hemming machine is disclosed in Japanese Published Unexamined Patent Application No. 2003-251417. In this conventional hemming machine, a pre-hemming process and a main hemming process are performed by oscillating and moving a frame supporting a pre-hemming tool and a main hemming tool in a straight line using a toggle link mechanism. Furthermore, when performing the main hemming process, the pre-hemming tool is retracted from the frame away from a space between a workpiece and the main hemming tool, which is positioned above the pre-hemming tool.
The hemming operation involves first oscillating the frame in relation to a base so that the pre-hemming tool and the main hemming tool are located above an edge part of the workpiece, which is on a die. The frame is then moved downward in a straight line to bring the pre-hemming tool nearer to the workpiece and to perform a pre-hemming operation. Next, the pre-hemming tool is moved so that it is retracted from the frame. Now, the main hemming process is performed by drawing the main hemming tool, which is at a position that is higher than the pre-hemming tool, closer to the workpiece by moving the frame further in a straight line. The frame is guided at this time by a cam groove formed in the base, and is oscillated and moved in a straight line.